STEP=1:30;
y=[6.2731    6.5202    6.5603    6.5755    6.5823    6.5887    6.5918    6.5952    6.5965    6.5972 6.5978    6.5985    6.6003    6.6017    6.6019    6.6020    6.6020    6.6020    6.6020    6.6020 6.6020    6.6020    6.6020    6.6020    6.6020    6.6020    6.6020    6.6020    6.6020    6.6020]
length(y)
length(STEP)
plot(STEP,y,'r-o','LineWidth',1.5,'MarkerSize',6);
grid on;
h1=xlabel('Number of iterations');
h2=ylabel('large-system approximation Sum Rate (bps/Hz)');
legend('PSO');